Development of novel approaches to behavioural test data analysis is of considerable im-portance to fundamental research as well as experimental neuropharmacology. Antipsy-chotic agents used to treat positive and negative symptoms in schizophrenia are of par-ticular interest to current research. Despite that antipsychotics exert potent effects on animal behaviour in simple behavioural tests, they can be difficult to distinguish fromother central nervous system-depressing agents, such as sedatives. In this paper, we pro-pose colour coding of video sequence as a method for the analysis of behavioural patternstructure in rats, using the effects of haloperidol, a typical antipsychotic, in the Openfield test, as an example. The study was carried out in outbred albino male rats weighing250–300 g. 3 min long video sequences of rat behaviour in the Open field were processedusing Python and the OpenCV library in the Google Colab 3 environment. Colour cod-ing allowed for the marking up and overlaying in a single frame the present (t = 0), near-est-future (t = 0.33 s), and the less-near-future (t = 1.66 s) location of an animal in thearena. Using the proposed method, we were able to detect specific effects of haloperidolon animal behavioural patterns which are undetectable using conventional behaviouraldata analysis techniques for this test. The three-timepoint colour coding method we pro-pose proved effective for data analysis and processing, and the results were in accordancewith other author’s data, obtained using computerized as well as conventional visualiza-tion techniques.Keywords: colour coding, behavioural testing, Open field, haloperidol, antipsychotics